1. Field of the Invention
The present invention relates to cycloid drives. More specifically, the present invention discloses an epicycloid planet gear mounted raised cam track or slotted cam track for converting rotational movement of a driveshaft into linear movement of an output object while utilizing the advantageous speed reduction and torque magnification properties of a cycloid drive.
2. Description of the Prior Art
A leadscrew is a screw used to translate rotary input motion into linear output motion. The conventional leadscrew is a threaded screw that mates with a nut. As the threaded screw rotates, the nut moves along the screw either forward or backward. A load connected to the nut moves along with the nut.
While useful in various applications the conventional leadscrew has numerous disadvantages.
One disadvantage is that the threaded screw and nut require high manufacturing precision and, so, are relatively high cost.
Another disadvantage is that very fine movements per rotation are difficult to achieve because of the difficulty of machining very fine pitch threads.
Also, conventional leadscrews must be well lubricated throughout their service life as high stiction (static friction) will require high start up forces after long periods of immobility if the leadscrew's lubrication layer isn't maintained.
Furthermore, applying force on the load attached to the nut can cause the conventional leadscrew to rotate or back drive. In many applications this is undesirable as contact with the load can cause unintentional movement of the leadscrew and change in the load position.
Moreover, conventional leadscrews driving offset loads can be relatively inefficient.
Another method for translating rotary motion into linear motion is by using a speed reduction gear train whose output gear causes a circular cam to rotate, thereby creating linear output motion of some driven component.
One disadvantage of using such a gear train driven cam to produce linear output motion is the complexity of the gear train required to reduce rotary input speed to a useful slower output speed at higher torque, particularly in compact devices such as a digital camera.
Another disadvantage is the tolerance stackup of so many mating components causes mechanical inefficiency and positional inaccuracy of the output device.
Therefore, there is need for an improved means of efficiently, compactly, accurately and economically translating rotational motion into linear motion.